code: def test_saturation_warning():
      rgb_img = np.random.uniform(size=(10, 10, 3))
      labels = np.ones((10, 10), dtype=np.int64)
      with expected_warnings(["saturation must be in range"]):
          label2rgb(labels, image=rgb_img, bg_label=0, saturation=2)
      with expected_warnings(["saturation must be in range"]):
          label2rgb(labels, image=rgb_img, bg_label=0, saturation=-1)
  
imports: import itertools
  import numpy
  import pytest
  from numpy.testing import assert_array_almost_equal, assert_array_equal, assert_no_warnings, assert_warns
  from skimage._shared.testing import expected_warnings
  from skimage.color.colorconv import hsv2rgb, rgb2hsv
  from skimage.color.colorlabel import label2rgb
label_desc: Use image node_id 22 for calling a global function with example usage: test_saturation_warning() without return types